chelicerate

[kə-lĭs′ər-āt′, -ĭt]

Any of various, mostly terrestrial arthropods of the subphylum Chelicerata, having a body divided into two main parts: a cephalothorax and an abdomen. Chelicerates have specialized feeding appendages (chelicerae) and lack antennae. Chelicerates include the arachnids and merostomes (horseshoe crabs) and are closely related to the extinct trilobites.